Quick update: My vet called and gave me the quotes. They said the CT will cost $1000, and the rhinoscopy will cost between $2k and $2500, depending on biopsies, if needed. Now, if they did the CT and saw something, they would have to do the rhinoscopy anyway.
So it could cost as little as $1000 or as much as $3500.
It's super frustrating. I can't seem to find anyone else online with the same problem to get experience or advice from